Bobbin holder

ABSTRACT

A bobbin holder is disclosed for rotatably fastening bobbins to bobbin creels. The bobbin holder comprises a rotatable assembly including a shell insertable into a recess in a bobbin to be held, bobbin catch means supported by the shell, and catch actuating means for extending and retracting the catch means to and from the exterior of the shell to hold and release a bobbin positioned about the shell. The bobbin holder further comprises a stationary assembly including a brake shoe, first spring means biasing the brake shoe against the rotatable assembly, frictional engagement means disposed adjacent the rotatable assembly, and second spring means biasing the frictional engagement means into contact with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly exceeding a preselected magnitude and biasing the frictional engagement means out of engagement with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly failing to exceed the preselected magnitude. The rotatable assembly shell is hollow and includes tubular walls defining apertures through which catch means may extend and an interior guide surface extending between the apertures and defining two indentation stops. The catch means is provided by an elongated pawl slidably disposed within the hollow shell with two pawl ends alternatively projectable out of the shell through the shell apertures and with a projecting pawl detent alternatively catchable in the two guide surface indentation stops. A spring loaded plunger is also disposed within the shell biasing the pawl projecting detent towards at least one of the guide surface indentation stops.

United States Patent [1 1 Whitehead, Sr. et al.

[ Dec. 24, 1974 BOBBIN HOLDER [22] Filed: Nov. 8, 1973 [21] Appl. No.: 414,130

[52] U.S. Cl. 242/130.2, 242/129.7 [51] Int. Cl. B65h 49/02, D03j 5/08 [58] Field of Search 242/129.7, 130.2; 68/198 [56] References Cited UNITED STATES PATENTS 3,389,876 6/1968 Whitehead, Sr. et al. 242/l30.2 3,400,899 9/1968 Tytgath 242/l30.2 3,565,364 2/1971 Numata 242/l30.2 3,625,452 12/1971 Noguera 242/l30.2

Primary ExaminerLeonard D. Christian Attorney, Agent, or FirmNewton, Hopkins & Ormsby [57] ABSTRACT A bobbin holder is disclosed for rotatably fastening bobbins to bobbin creels. The bobbin holder comprises a rotatable assembly including a shell insertable into a recess in a bobbin to be held, bobbin catch means supported by the shell, and catch actuating means for extending and retracting the catch means to and from the exterior of the shell to hold and release a bobbin positioned about the shell. The bobbin holder further comprises a stationary assembly including a brake shoe, first spring means biasing the brake shoe against the rotatable assembly, frictional engagement means disposed adjacent the rotatable assembly, and second spring means biasing the frictional engagement means into contact with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly exceeding a preselected magnitude and biasing the frictional engagement means out of engagement with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly failing to exceed the preselected magnitude. The rotatable assembly shell is hollow and includes tubular walls defining apertures through which catch means may extend and an interior guide surface extending between the apertures and defining two indentation stops. The catch means is provided by an elongated pawl slidably disposed within the hollow shell with two pawl ends alternatively projectable out of the shell through the shell apertures and with a projecting pawl detent alternatively catchable in the two guide surface indentation stops. A spring loaded plunger is also disposed within the shell biasing the pawl projecting detent towards at least one of the guide surface indentation stops.

12 Claims, 9 Drawing Figures PATENTED B5824 I974 sum 1 or 3 FIG /1 PATENTEDBE024|914 BOBBIN HOLDER BACKGROUND OF THE INVENTION This invention relates to bobbin holders for rotatably fastening bobbins to bobbin creels.

Today, bobbin holders used in rotatably fastening yarn and roving bobbins to bobbin creels typically comprise a hollow shell extending downwardly from a pen dant secured to overhanging creel structure. The shell is shaped to extend into an axial recess formed within and communicating with the top of the bobbin. Two or more pawls are pivotally mounted within the shell to alternatively extend to and from the exterior of the shell into contact with an interior surface of the bobbin to alternatively hold and release the bobbin from about the bobbin holder shell. Examples of such bobbin holders are disclosed in U. S. Pat. Nos. 3,400,899 and 3,389,876.

Early bobbin holders were freely rotatable with only bearing friction producing rotary drag. Present day industrial environments for bobbin creels however have come to include powerful blowers disposed in proximity with the bobbin holder to blow lint away from the bobbins. Other machinery productive of mechanical vibrations is now also present in proximity with the bobbin creels. Vibrations and air blasts from these machines have tended to impart rotary motion to the bobbin holders when they are not in use and therefore not under load. Such rotation of the bobbin holders is, of course, quite undesirable in that it may lead to an unwinding of the yarn or roving from the bobbins. To overcome this problem, bobbin holders have come to include brake means to inhibit the holders from rotating and unravelling yarn when not in use. Until recently the brakes were primarily in the form of exterior gravity types comprising pendant arms pivoted axially above the bobbin with the lower end thereof in contact with the peripheral surface of the roving or yarn wound on the bobbin. Where the bobbin holder supported relatively large amounts of roving such gravity brakes extended laterally outwardly from the axis of the holders to form a relatively large acute angle with the coincident bobbin and bobbin holder axes. This lateral extension caused a substantial portion of the weight of the pendant gravity brake to be applied against the roving. However, as roving was dispensed from the bobbin the peripheral diameter of the roving decreased causing the brake to assume more and more of a vertical orientation thereby applying less braking force to the bobbin through frictional engagement with the roving. This relatively linear decrease in braking power has proven undesirable since it has caused yarn tension during spinning operations to vary substantially. To solve this problem, internal bobbin holder braking means have recently been devised to provide improved yarn tension. The previously mentioned U. S. Pat. No. 3,400,899 exemplifies one such internal braking means. Though these brakes have provided an improvement over the older, external gravity types, they have failed to effect the variable drag on bobbin holders leading to relaively constant yarn tension.

In addition to the just described braking problems associated with bobbin holders of the prior art, these holders have also experienced problems with regard to their means of reliably catching and releasably holding bobbins about the bobbin holders. As previously mentioned, these catch means today typically include one or more pawls which, upon actuation, alternatively project out of and recede into the bobbin holder shells about which the bobbins are held. These pawls are actuated by manually raising a bobbin upwardly about the exterior of the bobbin holder shell and in doing so causing the bobbin to strike and pivot an upper exposed end portion of the pawl causing a lower end portion of the pawl disposed within the bobbin to extend outwardly into gripping engagement with the bobbin. When it is desired to remove the bobbin it again is raised thereby effecting another tripping action of the pawl causing the lower projecting end thereof to return within the bobbin holder shell and thereby permitting the bobbin to fall downwardly off of the shell. These so called gravity actuated pawl catch means, which are exemplified by that disclosed in US. Pat. No. 3,331,567, have proved unreliable in actual practice due to the previously described environmental conditions in which bobbin creels are disposed. In addition, they have failed to provide reliably positive response to the manual manipulations of workers rapidly mounting and unmounting bobbins thereon which has lead to a high rate of bobbin drop incidents.

Accordingly, it is a general object of the present invention to provide improved bobbin holders for rotatably fastening bobbins to bobbin creels.

More specifically, it is an object of the present invention to provide bobbin holders having improved brake means.

Another object of the invention is to provide bobbin holders having brake means providing drag which varies in relation with the weight of a bobbin supported on the bobbin holder so as to provide substantially constant tension in yarn or roving being spun off of the bobbin.

Yet another object of the invention is to provide bobbin holders having improved means for releasably holding and releasing bobbins supported thereon.

SUMMARY OF THE INVENTION In one form of the invention a bobbin holder is provided for rotatably fastening bobbins to bobbin creels. The bobbin holder comprises a rotatable assembly including a shell insertable into a recess in a bobbin to be held, bobbin catch means supported by the shell, and catch actuating means for alternatively extending and retracting at least a portion of the catch means to and from the exterior of the shell to alternatively catch and release a bobbin positioned about the shell. The bobbin holder further comprises a stationary assembly including a brake shoe, first spring means biasing the brake shoe against the rotatable assembly, frictional engagement means disposed adjacent the rotatable assembly, and second spring means biasing the frictional engagement means into contact with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly exceeding a preselected magnitude and biasing the frictional engagement means out of engagement with the rotatable assembly in response to the weight of a bobbin held on the rotatable assembly failing to exceed the preselected magnitude.

In another form of the invention, a bobbin holder is provided for rotatably fastening bobbins to bobbin creels and comprising a pendant, a cover mounted about a lower portion of the pendant, and a ball bearing carried by the pendant within the cover and including a first annular bearing race rotatable about the pendant. The shell is mounted to the first bearing race and is insertable into the recess in a bobbin to be held. An annular brake shoe is disposed upon the first bearing race. A compression spring is compressibly mounted between the cover and the brake shoe biasing the brake shoe against the first bearing race.

In yet another form of the invention a bobbin holder is provided for rotatably fastening bobbins to bobbin creels and comprising a hollow shell insertable into a recess in a bobbin to be held. The hollow shell includes tubular walls defining apertures and an interior guide surface extending between the apertures and defining indentation stops. An elongated pawl is slidably disposed within a hollow shell. The pawl has two ends alternatively projectable out of the shell through the apertures and a projecting detent alternatively catchable in the guide surface indentation stops. A spring loaded plunger is also provided biasing the pawl projecting detent downwardly towards at least one of the guide surface indentation stops.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a bobbin holder embodying principles of the present invention in one form;

FIG. 2 is an exploded view in perspective of a portion of the bobbin holder shown in FIG. 1;

FIG. 3 is an elevational view in cross section of the bobbin holder depicted in FIG. 1;

FIG. 4 is an elevational view in cross section of a portion of the bobbin holder shown in FIG. 3 taken along plane 44;

FIG. 5 is an elevational view in cross section of a portion of the bobbin holder shown in FIG. 3 taken along plane 5-5;

FIGS. 6-8 are elevational views in cross section of a portion of the bobbin holder shown in FIG. 3 illustrating an operative sequence of events in actuating the bobbin holder catch means; and,

FIG. 9 is a graph comparatively illustrating the braking effected by bobbin holders embodying the present invention and that of the prior art.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT Referring now in more detail to the drawings, those skilled in the art will recognize a bobbin holder of generally bullet shape with the nose pointing downwardly and comprising a shell made up of mating shell halves 1 and l joined together at their lower ends by an encircling compression ring 2 and at their upper ends by encircling lock ring 3. An actuation collar 4 is slidably disposed about the shell and prevented from sliding completely thereoff by compression ring 2. Near the upper ends of mating shell halves l and l are formed two half disc-shaped inwardly extending walls 5 which abut one another to provide separation between an upper cavity 6 and a lower cavity 7. To the uppermost end 8 of the mating shell halves l and l is rigidly mounted a rotatable bearing race 9. Between the rotatable race 9 and a relatively stationery race 11 is disposed a set of roller balls 12. Fitted snugly within an indenture in the rotatable race 9 is a hardened bearing lock 13. The stationery bearing race 11 accepts a pendant stud 14 which is threaded at one end and/at the other contains a head with a plurality of semi-conical protrusions 15. A brake spring 16 containing a hole at its center formed to mesh with the semi-conical protrusions 15 at the head of stud 14 is supported on the stud head.

These protrusions meshing with mating recesses in spring 16 prevent rotation of the spring during braking. The brake spring contains a set of leaves 17 extending upwardly against rotatable friction washer 21 so as to force the washer against the hardened steel bearing lock 13 under selected operating conditions. If desired, washer 21 may be omitted. Where used it may be formed of a soft plastic material such as acetal polymer.

Encircling stud 14 and resting on the top surface of brake spring 16 is compression spring 18. The upper end of the compression spring is compressed against bearing race 11 so as to prevent contact of bearing lock 13 with leaves 17 of brake spring 16 or washer 21 except under selected operating conditions as hereinafter explained. Threaded nut 19 is screwed the entire length of the threads on stud l4 and jammed against the bottom root of the thread so as to secure brake spring 16, compression spring 18 and the ball bearing in working proximity.

When a bobbin loaded with thread or the like is secured to the lower end of the holder, the weight of the bobbin exerts a downward force equal to its weight which force is transmitted through the holder shell to race 9. This downward force is counteracted by the upwardly exerted static support force supplied at the head of stud 14 through compression spring 18, race 11, and roller ball 12. When the bobbin weight exceeds a preselected magnitude, compression spring 18 compresses sufficiently to cause leaves 17 of brake spring 16 to force washer 21 into contact with the hardened steel bearing lock 13 thereby applying frictional resistance to the rotation of the rotatable bearing race 9 and shell. Compression spring 16 is sized in this particular embodiment so that complete compression is obtained at about 3 lbs. of bobbin weight. This provides a generally constant amount of frictional resistance at all bobbin weights in excess of 3 lbs. and then decreasing resistance from 3 lbs. to empty bobbin as shown by curve A in FIG. 9. By comparison, curve B depicts the varying tension provided by a typical gravity type bobbin brake of the prior art.

In addition to the frictional resistance supplied by leaves 17 of brake spring 16 is that applied by conical spring 25 compressedly disposed between brake shoe 20 upon the top of race 9 and dustcap 24. This frictional resistance is substantially constant for all bobbin weights. Obviously, for some specific applications one of these frictional resistance generating means may be omitted. Curve C, for example, illustrates the substantially constant tension provided by a bobbin holder of the type described without brake spring 16. With relatively lightweight bobbins, supporting fine yarns for example, the presence of brake spring 16 may not be necessary in order to effect relatively constant yarn tension. Brake shoe 20 is generally annular being bellshaped at its lower end and tapering inwardly thence forming a cylindrical vertical flange at its upper end. The bell-shaped lower end contacts the upper chamfered edge of rotational race 9 so as to form a dust and lint seal for the lower bearing cavity and yet permit angular displacement of the bobbin holder shell. The cylindrical vertical flange at the upper end of the brake shoe fits circumferentially outside the formed protrusion 23 extending downwardly from the top of dustcap 24. This protrusion is further formed so as to accept hex nut 19. Helical spring 25 is tapered so that its lower smaller end is slightly larger than the cylindrical vertical flange of the brake shoe and its upper, larger end is slightly smaller than the inside of the dustcap. The dustcap has a central hole in its top surface through which the threaded portion of stud 14 passes.

The combination of varying frictional resistance applied by brake spring 16 and constant frictional resistance applied by brake shoe 20 produces an excellent degree of rotational braking force for most bobbin weights. For very fine yarns and small packages, however, helical compression spring may be removed to lower the amount of tension required to rotate the bobbin to some 1.5 grams. Conversely, by eliminating spring brake l6 and using only the brake shoe with the helical compression spring 25 a small, substantially contant force may be provided.

Turning now to FIGS. 4-8, the bobbin holder catch mechanism is seen to include an actuator arm slidably disposed within shell half 1 having longitudinal slots 1A and IE to accept ears 30A and 30B of the actuator arm. The shell half also has a slot 1C near its lower end to accept the foot 30C end of the actuator arm 30. Bobbing shell half 1' contains an idler arm and a single slot 1 'C to accept the foot 40C of the idler arm.

In the bobbin engaged position shown in FIG. 5, actuator arm 30 is forced to its lowest vertical position by means of a plunger 50 and helical spring 51. In this engaged position the heel 31 of the actuator arm is detented with a protruding stop 53! formed in a guide surface within shell half 1. Similarly the heel 41 of idler 40 is engaged with protrusion 52 of shell half 1'. The foot 30C of the actuator and the foot 40C of the idler protrudes outside the bobbin shell at slots 1C and l'C respectively. The right ear 30B of the actuator members protrudes outsides the shell at 1B.

To disengage the bobbin, the catch mechanism operating collar 4 is slid upwardly to engage ear 30B. As the force exerted on the collar overcomes the resistance supplied by plunger 50 and spring 51 the actuator arm 30 is moved vertically upward causing point 32 on the actuator arm to come in contact with camming point 57 on the actuator shell. Operating collar 4 at this point prohibits movement of the ear 30A of the actuator arm so that the foot end rotates toward the inside of the shell due to bias provided by plunger 50 and spring 51 acting against ear 30B lifted by the collar. The movement of the foot 30C is guided by the formed interior of the bobbin shell. When the operating collar is extended to its uppermost limits, heel 31 of the actuator arm is above and over ridge 54 in the bobbin shell. When the operating collar 4 is lowered ear 30A of the actuator arm is forced outwardly by plunger 50 and heel 31 meshes with ridge 54 causing foot 30C to be contained completely within the bobbin shell. Idler arm 40 which is rotatably connected to the actuator arm 30 by means of a lug 42 on the idler arm fitted into a hole centered at the top of actuator arm, is rotated inwardly to be completely contained within the shell by reason of the force applied by plunger 50 on the top sloping edge of the idler arm as shown in FIG. 7.

In order to reengage a fresh bobbin the operating collar 4 is again moved vertically to engage ear 30A as shown in FIG. 8. As a result of the movement provided by plunger 50 and spring 51 and the force between collar 4 and ear 30A and camming action at point 55 on the shell and point 35 of the actuator arm the actuator arm is pivoted outwardly so that the heel 31 is forced downwardly by springs 51 and plunger 50 and the lower end forced outwardly by reason of the actuator arm heel 34 being guided by the inclined channel proceeding from ridge 54 to point 56 of the shell. At the lowest position heel 31 is again reengaged with ridge 53 and the heel 41 of the idler is reengaged with protrusion 52 so as to firmly position the actuator arm 30 and idler arm 40. In a small bobbin the two actuator arms would not necessarily go to the full bottom position.

It should be understood that many modifications may be made to the just described embodiment without departure from the spirit and scope of the invention as set forth in the following claims.

What is claimed is:

1. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising:

a. a rotatable assembly including a shell insertable into a recess in a bobbin to be held, bobbin catch means supported by said shell, and catch actuating means for extending and retracting at least a portion of said catch means to and from the exterior of said shell to catch and release a bobbin positioned about said shell; and

b. a stationary assembly including a brake shoe, first spring means biasing said brake shoe against said rotatable assembly, frictional engagement means disposed adjacent said rotatable assembly, and second spring means biasing said frictional engagement means into contact with said rotatable assembly in response to the weight of a bobbin held on said rotatable assembly exceeding a preselected magnitude and biasing said frictional engagement means out of engagement with said rotatable assembly in response to the weight of a bobbin held on said rotatable assembly failing to exceed said preselected magnitude.

2. A bobbin holder in accordance with claim 1 wherein said first spring means includes a first compression spring, and wherein said second spring means includes a second compression spring.

3. A bobbin holder in accordance with claim 1 wherein said frictional engagement means includes a plate disposing along a plane having a set of resilient leaves projecting off said plane.

4. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising:

a. a pendant;

b. a shell insertable into a recess in a bobbin to be held;

0. a bobbin catch means supported by said shell;

d. catch actuating means for extending and retracting said catch means to and from the exterior of said shell;

e. a ball bearing having a rotatable race mounted to said shell and a relatively stationary race supported by said pendant;

f. a brake shoe spring biased against said ball bearing rotatable race;

g. a compression spring compressibly disposed between said ball bearing stationary race and said pendant; and,

h. frictional engagement means supported on said pendant to brake said shell in response to compression of preselected magnitude of said spring.

5. A bobbin holder in accordance with claim 4 wherein said pendant includes a stud having a head; and wherein said frictional engagement means includes a disc supported on said stud head.

6. A bobbin holder in accordance with claim 5 wherein said frictional engagement means includes a set of leaf springs projecting from said disc.

7. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising:

a. a pendant;

b. a cover mounted about a lower portion of said pendant;

c. a ball bearing carried by said pendant within said cover and including a first annular bearing race adapted to rotate about said pendant;

d. a shell mounted to said first bearing race and insertable into a recess in a bobbin to be held;

e. an annular brake shoe disposed upon said first bearing race; and

f. a first compression spring compressibly mounted between said cover and said brake shoe thereby biasing said brake shoe against said first bearing race.

8. A bobbin holder in accordance with claim 7 wherein said bearing includes a second annular bearing race and a set of balls disposed between said first and second annular bearing, and wherein said bobbin holder further comprises a second compression spring compressibly mounted between said pendant and said second bearing race.

9. A bobbin holder in accordance with claim 8 comprising an annular set of leaf springs mounted to said pendant to engage said first bearing race when said second compression spring is compressed a predetermined distance.

10. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising:

a. a hollow shell insertable into a recess in a bobbin to be held and including tubular walls defining apertures through which pawls may extend, and an interior guide surface extending between the apertures and defining two indentation stops;

b. an elongated pawl slidably disposed within said hollow shell and having two pawl ends alternatively projectable out of said shell through said apertures and a projecting detent alternatively catchable in said two guide surface indentation stops; and,

c. a spring loaded plunger biasing said pawl projecting detent towards at least one of said guide surface indentation stops.

11. A bobbin holder in accordance with claim 10 comprising a second elongated pawl pivoted to said elongated pawl.

12. A bobbin holder in accordance with claim 10 wherein said guide surface includes a camming surface against which said pawl slides and pivots. 

1. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising: a. a rotatable assembly including a shell insertable into a recess in a bobbin to be held, bobbin catch means supported by said shell, and catch actuating means for extending and retracting at least a portion of said catch means to and from the exterior of said shell to catch and release a bobbin positioned about said shell; and b. a stationary assembly including a brake shoe, first spring means biasing said brake shoe against said rotatable assembly, frictional engagement means disposed adjacent said rotatable assembly, and second spring means biasing said frictional engagement means into contact with said rotatable assembly in response to the weight of a bobbin held on said rotatable assembly exceeding a preselected magnitude and biasing said frictional engagement means out of engagement with said rotatable assembly in response to the weight of a bobbin held on said rotatable assembly failing to exceed said preselected magnitude.
 2. A bobbin holder in accordance with claim 1 wherein said first spring means includes a first compression spring, and wherein said second spring means includes a second compression spring.
 3. A bobbin holder in accordance with claim 1 wherein said frictional engagement means includes a plate disposing along a plane having a set of resilient leaves projecting off said plane.
 4. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising: a. a pendant; b. a shell insertable into a recess in a bobbin to be held; c. a bobbin catch means supported by said shell; d. catch actuating means for extending and retracting said catch means to and from the exterior of said shell; e. a ball bearing having a rotatable race mounted to said shell and a relatively stationary race supported by said pendant; f. a brake shoe spring biased against said ball bearing rotatable race; g. a compression spring compressibly disposed between said ball bearing stationary race and said pendant; and, h. frictional engagement means supported on said pendant to brake said shell in response to compression of preselected magnitude of said spring.
 5. A bobbin holder in accordance with claim 4 wherein said pendant includes a stud having a head; and wherein said frictional engagement means includes a disc supported on said stud head.
 6. A bobbin holder in accordance with claim 5 wherein said frictional engagement means includes a set of leaf springs projecting from said disc.
 7. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising: a. a pendant; b. a cover mounted about a lower portion of said pendant; c. a ball bearing carried by said pendant within said cover and including a first annular bearing race adapted to rotate about said pendant; d. a shell mounted to said first bearing race and insertable into a recess in a bobbin to be held; e. an annular brake shoe disposed upon said first bearing race; and f. a first compression spring compressibly mounted between said cover and said brake shoe thereby biasing said brake shoe against said first bearing race.
 8. A bobbin holder in accordance with claim 7 wherein said bearing includes a second annular bearing race and a set of balls disposed between said first and second annular bearing, and wherein said bobbin holder further comprises a second compression spring compressibly mounted between said pendant and said second bearing race.
 9. A bobbin holder in accordance with claim 8 comprising An annular set of leaf springs mounted to said pendant to engage said first bearing race when said second compression spring is compressed a predetermined distance.
 10. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising: a. a hollow shell insertable into a recess in a bobbin to be held and including tubular walls defining apertures through which pawls may extend, and an interior guide surface extending between the apertures and defining two indentation stops; b. an elongated pawl slidably disposed within said hollow shell and having two pawl ends alternatively projectable out of said shell through said apertures and a projecting detent alternatively catchable in said two guide surface indentation stops; and, c. a spring loaded plunger biasing said pawl projecting detent towards at least one of said guide surface indentation stops.
 11. A bobbin holder in accordance with claim 10 comprising a second elongated pawl pivoted to said elongated pawl.
 12. A bobbin holder in accordance with claim 10 wherein said guide surface includes a camming surface against which said pawl slides and pivots. 